Additive manufactured bearing cap for temperature reduction on bearing cap wetted wall

Abstract

In a traditional bearing cap, the temperature of the oil-wetted surface that defines the oil sump may experience high temperatures, which can result in oil degradation, oil varnish, and coking. Accordingly, a bearing cap is disclosed that reduces the temperatures experienced by the oil-wetted surface. In particular, the bearing cap may comprise one or more air insulation cavities, between the surface that is exposed to heated air and the oil-wetted surface that defines the oil sump, to provide a thermal barrier between the two surfaces.

What is claimed is: 
     
       1. A bearing cap for a gas turbine engine, the bearing cap comprising:
 a first surface on a first side, wherein the first surface is annular around a longitudinal axis; 
 a second surface on a second side that is opposite and downstream from the first side, wherein the second surface is annular around the longitudinal axis; 
 one or more air insulation cavities between the first surface and the second surface, wherein each of the one or more air insulation cavities is annular around the longitudinal axis; and 
 an annular mixed air cavity upstream from the one or more air insulation cavities. 
 
     
     
       2. The bearing cap of  claim 1 , wherein, in a cross-sectional plane that includes the longitudinal axis, at least a portion of at least one of the one or more air insulation cavities extends away from the longitudinal axis at a non-zero angle with respect to the longitudinal axis. 
     
     
       3. The bearing cap of  claim 1 , wherein, in a cross-sectional plane that includes the longitudinal axis, at least a portion of at least one of the one or more air insulation cavities extends away from the longitudinal axis at a non-zero, non-perpendicular angle with respect to the longitudinal axis. 
     
     
       4. The bearing cap of  claim 1 , wherein, in a cross-sectional plane that includes the longitudinal axis, a first portion of at least one of the one or more air insulation cavities extends away from the longitudinal axis at a non-zero first angle with respect to the longitudinal axis, and a second portion of the at least one air insulation cavity extends away from the longitudinal axis at a second angle with respect to the longitudinal axis, wherein the second angle is different from the first angle. 
     
     
       5. A bearing cap for a gas turbine engine, the bearing cap comprising:
 a first surface on a first side, wherein the first surface is annular around a longitudinal axis; 
 a second surface on a second side that is opposite and downstream from the first side, wherein the second surface is annular around the longitudinal axis; 
 one or more air insulation cavities between the first surface and the second surface, wherein each of the one or more air insulation cavities is annular around the longitudinal axis; 
 wherein, in a cross-sectional plane that includes the longitudinal axis, a radially outer first portion of at least a first one of the one or more air insulation cavities extends away from the longitudinal axis and towards the second side at a first angle with respect to the longitudinal axis, and a radially inner second portion of the first air insulation cavity extends away from the longitudinal axis and towards the first side at a second angle with respect to the longitudinal axis. 
 
     
     
       6. The bearing cap of  claim 5 , wherein, in the cross-sectional plane, one or both of a radially innermost end of the first air insulation cavity or a radially outermost end of the first air insulation cavity has a teardrop shape. 
     
     
       7. The bearing cap of  claim 5 , further comprising one or more powder removal holes extending from one or both of a radially innermost end of the first air insulation cavity or a radially outermost end of the first air insulation cavity to an external environment of the bearing cap. 
     
     
       8. The bearing cap of  claim 5 , further comprising one or more powder removal holes extending from a vertex formed at a point at which the first portion and the second portion of the first air insulation cavity meet. 
     
     
       9. The bearing cap of  claim 5 , wherein the one or more air insulation cavities are a plurality of air insulation cavities, and wherein, in the cross-sectional plane, a second one of the plurality of air insulation cavities is shorter in total length than the first air insulation cavity. 
     
     
       10. The bearing cap of  claim 9 , wherein, in the cross-sectional plane, the second air insulation cavity is parallel to the longitudinal axis. 
     
     
       11. The bearing cap of  claim 10 , wherein the second air insulation cavity is downstream from a radially innermost end of the first air insulation cavity. 
     
     
       12. The bearing cap of  claim 9 , further comprising one or more powder removal holes extending from at least one end of the second air insulation cavity to an external environment of the bearing cap. 
     
     
       13. The bearing cap of  claim 1 , wherein the second surface defines an oil sump on the second side. 
     
     
       14. The bearing cap of  claim 13 , wherein, in the cross-sectional plane, a profile of the one or more air insulation cavities matches a profile of the oil sump. 
     
     
       15. The bearing cap of  claim 1 , further comprising one or more seal rings on a radially inward facing surface of the bearing cap that encircles a central channel through the bearing cap. 
     
     
       16. A gas turbine engine comprising:
 a compressor; 
 a combustor downstream from the compressor; 
 a turbine downstream from the combustor; and 
 the bearing cap of  claim 1 , positioned between the compressor and the combustor. 
 
     
     
       17. A bearing cap for a gas turbine engine, the bearing cap comprising:
 a first surface on a first side, wherein the first surface is annular around a longitudinal axis; 
 a second surface on a second side that is opposite and downstream from the first side, wherein the second surface is annular around the longitudinal axis and defines an oil sump on the second side; and 
 a plurality of air insulation cavities between the first surface and the second surface, wherein each of the plurality of air insulation cavities is annular around the longitudinal axis, and wherein the plurality of air insulation cavities comprises
 a first air insulation cavity that, in a cross-sectional plane that includes the longitudinal axis, comprises a radially outer first portion that extends away from the longitudinal axis and towards the second side at a first non-zero angle with respect to the longitudinal axis, and a radially inner second portion that extends away from the longitudinal axis and towards the first side at a second non-zero angle with respect to the longitudinal axis, wherein a profile of the first air insulation cavity matches a profile of the oil sump, and 
 a second air insulation cavity positioned downstream from a radially innermost end of the first air insulation cavity.